The boys wanted to come up with a way to test for sour milk, but then a milk lobby in California caught wind of it and sent a big warning.

Nine-year-old Cameron Behram and his 7-year-old brother came up with science project idea: How to figure out if milk was sour without smelling it.

It was something he said his mom always asked them to do.

Their plan?

They researched it on Wikipedia and learned that milk sours by the bacteria that is multiplying in it, making it more acidic.

So the brothers decided to use test strips. If the acid level was too high, the strip would change color and the milk was sour. The family created a website to spread the word to relatives and friends and called it gotsourmilk.com.

Then they got a letter from an attorney representing the milk lobby saying they were violating their copyright.

According to the letter, the lawyers represented the California Milk Processor Board, the owner of the Got Milk? service and trademarks.

The letter said the boys website gotsourmilk.com was "...confusingly similar to our client's ‘got milk’ and the addition of ‘sour’ is not sufficient to alleviate the likelihood of confusion.”

Even though the family said they bought the domain name, the lawyers warned, "...our client is authorized to bring a civil lawsuit against you."

Stunned their little website reached so far up the food chain, they agreed to rename it.

It's now dontbeasourpuss.com. The science project is still a go with a lesson learned.

When asked about the case by ABC7, the milk lobby spoke well of the kids' project and wished them well.

"We have to police our trademark," Steve James, executive director of the California Milk Processor Board, tells ABC7 News. "We can't pick and choose who we send our cease-and-desist orders to. They complied quickly. It is a well designed project and well thought out and we wish them luck."